Nitroxyl derivatives with glycidyl or alkylcarbonyl groups as initiators for radical polymerization

ABSTRACT

Glycidyl and alkylcarbonyl functional nitroxide radical polymerization initiator compounds of formula (Ia) or (Ib),                    
     where R 1 , R 2  and A are as defined within, 
     R 3  is a radical of formula (II)                    
      where 
     X is phenylene, naphthylene or biphenylene, which are unsubstituted or substituted by NO 2 , halogen, amino, hydroxy, cyano, carboxy, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylamino or di(C 1 -C 4 alkyl)amino; 
     the R 12  are independently of each other H or CH 3 ; 
     D is a group                    
      a group C(O)—R 13  or a group C(O)—R 9 —C(O)—R 13 ; 
     R 13  is C 1 -C 18 alkyl and 
     m is a number from 1 to 4, provide polymeric resin products having low polydispersity, polymerization processes that proceed with good monomer to polymer conversion efficiencies and polymers that contain a glycidyl or alkylcarbonyl group.

The present invention relates to glycidyl or alkylcarbonyl functionalnitroxyle derivatives, a polymerizable composition comprising a) atleast one ethylenically unsaturated monomer and b) a glycidyl oralkylcarbonyl functional nitroxide initiator compound. Further aspectsof the present invention are a process for polymerizing ethylenicallyunsaturated monomers, the use of glycidyl or alkylcarbonyl functionalnitroxide initiators for radical polymerization.

More specifically, in one of its aspects the present invention relatesto polymerizable compositions and polymerization processes which providepolymeric resin products having low polydispersity, which polymerizationprocesses proceed with good monomer to polymer conversion efficiencies.In particular, this invention relates to stable free radical-mediatedpolymerization processes which provide homopolymers, random copolymers,block copolymers, multiblock copolymers, graft copolymers and the like,at enhanced rates of polymerization and enhanced monomer to polymerconversions. The polymers produced by the present invention contain aglycidyl or alkylcarbonyl group attached to the starting molecule of theradical chain reaction.

Polymers or copolymers prepared by free radical polymerization processesinherently have broad molecular weight distributions or polydispersitieswhich are generally higher than about four. One reason for this is thatmost of the free radical initiators have half lives that are relativelylong, ranging from several minutes to many hours, and thus the polymericchains are not all initiated at the same time and the initiators providegrowing chains of various lengths at any time during the polymerizationprocess. Another reason is that the propagating chains in a free radicalprocess can react with each other in processes known as combination anddisproportionation, both of which are irreversibly chain-terminatingreaction processes. In doing so, chains of varying lengths areterminated at different times during the reaction process, resulting inresins consisting of polymeric chains which vary widely in length fromvery small to very large and which thus have broad polydispersities. Ifa free radical polymerization process is to be used for producing narrowmolecular weight distributions, then all polymer chains must beinitiated at about the same time and termination of the growingpolymer-chains by combination or disproportionation processes must beavoided.

Conventional radical polymerization reaction processes pose varioussignificant problems, such as difficulties in predicting or controllingthe molecular weight, the polydispersity and the modality of thepolymers produced. These prior art polymerization processes producepolymers having broad polydispersities and in some instances, lowpolymerization rates. Furthermore, free radical polymerization processesin bulk of the prior art are difficult to control because thepolymerization reaction is strongly exothermic and an efficient heatremoval in the highly viscous polymer is mostly impossible. Theexothermic nature of the prior art free radical polymerization processesoften severely restricts the concentration of reactants or the reactorsize upon scale-up. In case that additional functional groups, such asglycidyl groups are present in one of the monomers, these may betransformed into undesired groups under such reaction conditions.

Due to the above mentioned uncontrollable polymerization reactions, gelformation in conventional free radical polymerization processes are alsopossible and cause broad molecular weight distributions and/ordifficulties during filtering, drying and manipulating the productresin.

U.S. Pat. No. 4,581,429 to Solomon et al., issued Apr. 8, 1986,discloses a free radical polymerization process which controls thegrowth of polymer chains to produce short chain or oligomerichomopolymers and copolymers, including block and graft copolymers. Theprocess employs an initiator having the formula (in part) R′R″N—O—X,where X is a free radical species capable of polymerizing unsaturatedmonomers. The reactions typically have low conversion rates.Specifically mentioned R′R″N—O. radical groups are derived fromtetraethylisoindoline, tetrapropylisoindoline, tetramethylpiperidine,tetramethylpyrrolidine or di-t-butylamine.

The radical initiators, polymerization processes and resin products ofthe present invention have an additional glycidyl or alkylcarbonylgroup, which can be used for further reactions. The resulting resins areuseful in many applications.

The glycidyl or alkylcarbonyl group of the present initiatorsremainsessentially unchanged during the radical polymerization reaction.Therefore the radical initiators of the present invention offer thepossibility, after the radical polymerizabon is accomplished or stopped,to react the glycidyl group of the oligomers or polymers in a secondstep with nucleophiles such as alcohols, mercaptanes, amines, metalorganic compounds or the like, thereby changing the properties of theoligomers or polymers.

The glycidyl group of the initiators can also be reacted in a first stepfor example by anionic polymerization in the presence of for exampledicyandiamide, butyl-Lithium or other strong bases leading tooligomeric/polymeric radical initiators.

S. Kobatake et al, Macromolecules 1997, 30, 4238-4242 and in WO 97/36894disclose the anionic polymerization of butadiene in the presence ofcompound (a) which contains a glycidyl group in a side chain. Thiscompound acts as a terminating reagent for the anionic polymerization ofbutadiene.

The resulting macromolecule can be further used as a macroinitiator forradical polymerization and for preparing block copolymers containing apoylbutadiene segment.

The present invention provides initiators for radical polymerizationwhich contain the glycidyl or alkylcarbonyl group attached directly orseparated by a spacer group to the aryl group. The initiators show ahigh reactivity, good rates of polymerization and good monomer topolymer conversions.

The remaining glycidyl or alkylcarbonyl group is highly reactive towardsnucleophiles and can readily be transformed into other chemical groups idesired.

The compounds of the present invention are also useful as terminatingagents in the anionic polymerization of for example butadiene asdescribed in WO 97136894.

The polymerization processes and resin products of the present inventionare useful in many applications, including a variety of specialtyapplications, such as for the preparation of block copolymers which areuseful as compatibilizing agents for polymer blends or dispersing agentsfor coating systems or for the preparation of narrow molecular weightresins or oligomers for use in coating technologies and thermoplasticfilms or as toner resins and liquid immersion development ink resins orink additives used for electrophotographic imaging processes.

Surprisingly, it has been found that it is possible to produce polymersor copolymers of narrow polydispersity and a high monomer to polymerconversion even at relative low temperatures and at short reactiontimes, leaving the glycidyl group essentially unchanged. The resultingpolymers/copolymers are of high purity and in many cases colorless,therefore not requiring any further purification.

One subject of the present invention is to provide new initiators offormula (Ia) or (Ib)

wherein the R₁, are each independently of one another hydrogen, halogen,NO₂, cyano,

—CONR₅R₆, —(R₉)COOR₄, —C(O)—R₇, —OR₈, —SR₈, —NHR₈, —N(R₈)₂, carbamoyl,di(C₁-C₁₈alkyl)carbamoyl,

—C(═NR₅)(NHR₆); unsubstituted C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkynyl,C₇-C₉phenylalkyl, C₃-C₁₂cycloalkyl or

C₂-C₁₂heterocycloalkyl; or

C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈ alkynyl, C₇-C₉phenylalkyl,C₃-C₁₂cycloalkyl or C₂-C₁₂heterocycloalkyl, which are substituted byNO₂, halogen, amino, hydroxy, cyano, carboxy, C₁-C₄alkoxy,C₁-C₄alkylthio, C₁-C₄alkylamino or di(C₁-C₄alkyl)amino; or phenyl,naphthyl, which are unsubstituted or substituted by C₁-C₄alkyl,C₁-C₄alkoxy, C₁-C₄alkylthio, halogen, cyano, hydroxy, carboxy,C₁-C₄alkylamino or di(C₁-C₄alkyl)amino;

R₄ is hydrogen, C_(1-C) ₁₈alkyl, phenyl, an alkali metal cation or atetraalkylammonium cation;

R₅ and R₆ are hydrogen, C₁-C₁₈alkyl, C₂-C₁₈alkyl which is substituted byat least one hydroxy group or, taken together, form a C₂-C₁₂alkylenebridge or a C₂-C₁₂-alkylene bridge interrupted by at least one O or/andNR₈ atom;

R₇ is hydrogen, C₁-C₁₈alkyl or phenyl;

R₈ is hydrogen, C₁-C₁₈alkyl or C₂-C₁₈alkyl which is substituted by atleast one hydroxy group;

R₉ is C₁-C₁₂alkylene or a direct bond;

or all R₁ form together the residue of a polycyclic cycloaliphatic ringsystem or a polycyclic heterocycloaliphatic ring system with at leastone di- or trivalent nitrogen atom;

the R₂ are independently of each other phenyl or C₁-C₆alkyl or twotogether with the linking carbon atom form a C₅-C₆cycloalkyl group;

A is a divalent group required to form a cyclic 5-, 6- or 7-memberedring and

R₃ is a radical of formula (II)

 wherein

X is phenylene, naphthylene or biphenylene, which are unsubstituted orsubstituted by NO₂, halogen, amino, hydroxy, cyano, carboxy,C₁-C₄alkoxy, C₁-C₄alkylthio, C₁-C₄alkylamino or di(C₁-C₄alkyl)amino; theR₁₂ are independently of each other H or CH₃;

D is a group

 a group C(O)—R₁₃ or a group C(O)—R₉—C(O)—R₁₃;

R₁₃ is C₁-C₁₈alkyl and

m is a number from 1 to 4.

Halogen is fluoro, chloro, bromo or iodo.

The alkyl radicals in the various substituents may be linear orbranched. Examples of alkyl containing 1 to 18 carbon atoms are methyl,ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl,2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.

The alkenyl radicals in the various substituents may be linear orbranched. Examples of C₂-C₁₈ alkenyl are vinyl, allyl, 2-methylallyl,butenyl, hexenyl, undecenyl and octadecenyl. Preferred alkenyls arethose, wherein the carbon atom in the 1-position is saturated and wherethe double bond is not activated by substituents like O, C═O, and thelike.

Examples of C₂-C₁₈alkynyl are ethynyl,2-butynyl, 3hexynyl, 5-undecynyl,6-octadecynyl. The alkynyl radicals may be linear or branched.

C₇-C₉phenylalkyl is for example benzyl, phenylpropyl, α,α-dimethylbenzylor α-methylbenzyl.

C₃-C₁₂cycloalkyl which is unsubstituted or substituted by 1, 2 or 3C₁-C₄alkyl is typically cyclopropyl, cyclopentyl, methylcyclopentyl,dimethylcyclopentyl, cyclohexyl, methylcyclohexyl.

Alkyl substituted by —OH is typically 2-hydroxyethyl, 2-hydroxypropyl or2-hydroxybutyl. C₁-C₁₈Alkyl substituted by C₁-C₈alkoxy, preferably byC₁-C₄alkoxy, in particular by methoxy or ethoxy, is typically2-methoxyethyl, 2-ethoxyethyl, 3-methoxypropyl, 3-ethoxypropyl,3-butoxypropyl, 3-octoxypropyl and 4-methoxybutyl.

C₁-C₁₈Alkyl substituted by di(C₁-C₄alkyl)amino is preferably e.g.dimethylamino, diethylamino, 2dimethylaminoethyl, 2-diethylaminoethyl,3-dimethylaminopropyl, 3-diethylaminopropyl, 3-dibutylaminopropyl and4-diethylaminobutyl.

C₁-C₁₈Alkyl substituted by C₁-C₄alkylamino is preferably e.g.methylamino, ethylamino, 2-methylaminoethyl, 2-ethylaminoethyl,3-methylaminopropyl, 3-ethylaminopropyl, 3-buty-aminopropyl and4-ethylaminobutyl.

C₁-C₈Alkoxy and, preferably C₁-C₄alkoxy, are typically methoxy, ethoxy,propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy,heptoxy or octoxy.

C₁-C₄Alkylthio is typically thiomethyl, thioethyl, thiopropyl,thiolsopropyl, thiobutyl and thioisobutyl.

C₂-C₁₂heterocycloalkyl is typically oxirane, 1,4-dioxane,tetrahydrofuran, γbutyrolactone, ε-caprolactam, oxirane, aziridine,diaziridine, pyrrole, pyrrolidine, thlophen, furan, pyrazole, imidazole,oxazole, oxazolidine, thiazole, pyran, thiopyran, piperidine ormorpholine.

Examples of C₂-C₁₂alkylene bridges, preferably of C₂-C₆alkylene bridges,are ethylene, propylene, butylene, pentylene, hexylene.

C₂-C₁₂alkylene bridges interrupted by at least one N or O atom are, forexample, —CH₂—O—CH₂—CH₂, —CH₂—O—CH₂—CH₂—CH₂,—CH₂—O—CH₂—CH₂—CH₂—CH₂—CH₂—O—CH₂—CH₂—O—CH₂—, —CH₂—NH—CH₂—CH₂,—CH₂—NH—CH₂—CH₂—CH₂, —CH₂—NH—CH₂—CH₂—CH₂—CH₂—, —CH₂—NH—CH₂—CH₂—NH—CH₂—or —CH₂—NH—CH₂—CH₂ —O—CH₂—.

Phenyl substituted by 1, 2 or 3 C₁-C₄alkyl or C₁-C₄alkoxy is typicallymethylphenyl, dimethylphenyl, trimethylphenyl, t-butylphenyl,di-t-butylphenyl, 3,5-di-t-butyl-4-methylphenyl, methoxyphenyl,ethoxyphenyl and butoxyphenyl.

Examples of polycyclic cycloaliphatic ring systems are adamantane,cubane, twistane, norbornane, bicyclo[2.2.2]octane or bicyclo[3.2.1]octane.

An example of a polycyclic heterocycloaliphatic ring system ishexamethylentetramine (urotropine).

Examples for a divalent group A required to form a cyclic 5-, 6- or7-membered ring are: C₂-C₄alkylene, C₂-C₄alkenylene, C₂-C₄alkinylene,1,2 phenylene which groups may be unsubstituted or substituted by NO₂,halogen, amino, hydroxy, cyano, carboxy, carbonyl, C₁-C₁₈ alkoxy, C₁-C₁₈acyloxy, benzoyloxy, C₁-C₁₈alkylthio, C₁-C₁₈alkylamino ordi(C₁-C₁₈alkyl)amino or phenyl.

When A has the meaning of C₂-C₄alkylene or C₂-C₄alkenylene, these groupsmay also be interrupted by an O or N atom.

C₂-C₄alkylene bridges interrupted by at least one N or O atom are, forexample, —CH₂—O—CH₂—CH₂, —CH₂—O—CH₂—, —O—CH₂—CH₂—,—O—CH₂—O—CH₂—,—CH₂CH₂—CH₂—, —NH—CH₂—, —CH₂—, —NH—CH₂—NH—CH₂—, —O—CH₂— or —CH₂—O—C(O)—.

The C-atom to which the substituents R₁ are bound is preferably asecondary or tertiary C-atom more preferably it is a tertiary C-atom.

Preferred is a compound of formula (Ia) or (Ib), wherein the

R₁ are each independently of one another NO₂, cyano, —(R₉)COOR₄,—CONR₅R₆, —C(O)—R₇, —OR₈, carbamoyl, di(C₁-C,₁₈alkyl)carbamoyl,—C(═NR₅)(NHR₆);

unsubstituted C₁-C₈alkyl or C₅-C₇cycloalkyl;

or phenyl, which is unsubstituted or substituted by C₁-C₄alkyl,C₁-C₄alkoxy, cyano, hydroxy, carboxy, C₁-C₄alkylamino ordi(C₁-C₄alkyl)amino;

R₄ is C₁-C₈alkyl, phenyl, an alkali metal cation or a tetraalkylammoniumcation;

R₅ and R₆ are hydrogen, C₁-C₈alkyl, C₂-C₈alkyl which is substituted byat least one hydroxy group or, taken together, form a C₂-C₆alkylenebridge;

R₇ is, C₁-C₈alkyl or phenyl;

R₈ is C₁-C₈alkyl or C₂-C₈alkyl which is substituted by at least onehydroxy group;

R₉ is C₁-C₄alkylene or a direct bond;

the R₂ are independently C₁-C₆alkyl;

A is a divalent group required to form a cyclic 5-, 6- or 7-memberedring and

R₃ is a radical of formula (II)

 wherein

X is phenylene, naphthylene or biphenylene, which are unsubstituted orsubstituted by NO₂, halogen, amino or hydroxy;

the R₁₂ are independently of each other H or CH₃;

D is a group

 or a group C(O)—R₁₃;

R₁₃ is C₁-C₄alkyl and

m is a number from 1 to 4.

More preferred is a compound of formula (Ia) or (Ib), wherein the group

is

the R₂ are independently C₁-C₆alkyl;

A is a divalent group required to form a cyclic 5-, 6- or 7-memberedring and

R₃ is a radical of formula (II)

 wherein

X is phenylene, naphthylene or biphenylene;

one R₁₂ is H and the other R₁₂ is CH₃;

D is a group

 or a group C(O)—R₁₃;

R₁₃ is CH₃ and

m is a number from 1 to 2.

Particularly preferred is a compound of formula (Ib), wherein

the R₂ are independently CH₃ or C₂H₅;

A is a divalent group required to form a cyclic 5-or 6- membered ringand

R₃ is a radical of formula (II)

 wherein

X is phenylene, naphthylene or biphenylene;

one R₁₂ is H and the other R₁₂ is CH₃;

D is a group

 or a group C(O)—R₁₃;

R₁₃ is CH₃ and

m is a number from 1 to 2.

Most preferred is a compound of formula (III)

wherein

R₃ has the meaning as defined above;

Y is H, OR₁₀, NR₁₀R₁₁, —O—C(O)—R₁₀ or NR₁₁—C(O)—R₁₀;

R₁₀ and R₁₁ independently are hydrogen, phenyl, C₁-C₁₈alkyl,C₂-C₁₈alkenyl, C₂-C₁₈alkinyl or C₂-C₁₈alkyl which is substituted by atleast one hydroxy group or, if Y is NR₁₀R11, taken together, form aC₂-C₁₂alkylene bridge or, a C₂-C₁₂alkylene bridge interrupted by atleast one O atom.

Amongst the most preferred compounds those are of particular use,wherein

R₃ is

 or

Y is H, OR₁₀, NR₁₀R₁₁, —O—C(O)—R₁₀ or NR₁₁—C(O)—R₁₀;

R₁₀ and R₁₁ are independently hydrogen or C₁-C₆alkyl.

A further subject of the present invention is a polymerizablecomposition, comprising

a) at least one ethylenically unsaturated monomer or oligomer, and

b) an initiator compound of formula (Ia) or (Ib).

Suitable initiator compounds and examples for the different groups andsubstituents A, Y, X and R₁ to R₁₁ are already mentioned including theirpreferences.

Typically the amount of the initiator compound of formula (Ia) or (Ib)is in the range of 0.01 mol-% to 30 mol-% based on the monomer, oligomeror monomer/oligomer mixture used.

If monomer mixtures are used the average molecular weight is taken forcalculating mol-%.

The initiator compound of formula (Ia) or (Ib) is preferably present inan amount of 0.01 mol-% to 10 mol-%, more preferably in an amount of0.05 mol-% to 5 mol-%, based on the monomer, oligomer ormonomer/oligomer mixture used.

The monomers suitable for use in the present invention may bewater-soluble or water-insoluble. Water soluble monomers containtypically a salt of a carboxylic acid group. Water insoluble monomersare typically free of acid and phenolic groups. Typical metal atoms areNa, K or Li.

Typical monoethylenically unsaturated monomers free of carboxylic acidand phenolic groups which are suitable for this invention include thealkyl esters of acrylic or methacrylic acids such as methyl acrylate,ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate,butyl methacrylate and isobutyl methacrylate; the hydroxyalkyl esters ofacrylic or methacrylic acids, such as hydroxyethyl acrylate,hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropylmethacrylate; acrylamide, methacrylamide, N-tertiary butylacrylamide,N-methylacrylamide, N,N-dimethylacrylamide; acrylonitrile, methacrylonitrile, allyl alcohol, dimethylaminoethyl acrylate, dimethylaminoethylmethacrylate, phosphoethyl methacrylate, N-vinylpyrrolidone,N-vinylformamide, N-vinylimidazole, vinyl acetate, conjugated dienessuch as butadiene or isoprene, styrene, styrenesulfonic acid salts,vinylsulfonic acid salts and 2-acrylamido-2-methylpropane-sulfonic acidsalts and acryloil chloride.

Preferred ethylenically unsaturated monomers or oligomers are selectedfrom the group consisting of styrene, substituted styrene, conjugateddienes, acrolein, vinyl acetate, (alkyl)acrylic acidanhydrides,(alkyl)acrylic acid salts, (alkyl)acrylic esters or (alkyl)acrylamides.

Particularly preferred ethylenically unsaturated monomers are styrene,α-methyl styrene, p-methyl styrene or butadiene.

In a most preferred composition the ethylenically unsaturated monomer isstyrene.

Preferred acrylates are methylacrylate, ethylacrylate, butylacrylate,isobutylacrylate, tert. butylacrylate, hydroxyethylacrylate,hydroxypropylacrylate, dimethylaminoethylacrylate, glycidylacrylates,methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate,hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate,dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates,acrylonitrile, acrylamide or methacrylamide.

Examples for C₈-C₁₆ ethylenically unsaturated phenolics, which may alsobe used as comonomers include 4-hydroxy styrene, 4-hydroxy, α-methylstyrene, and 2,6-ditert. butyl, 4-vinyl phenol.

Another class of carboxylic acid monomers suitable for use as comonomersin this invention are the alkali metal and ammonium salts ofC₄-C₆-ethylenically unsaturated dicarboxylic acids. Suitable examplesinclude maleic acid, maleic anhydride, itaconic acid, mesaconic acid,fumaric acid and citraconic acid. Maleic anhydride (and itaconic acidare) is the preferred monoethylenically unsaturated dicaiboxylic acidmonomer(s).

The acid monomers suitable for use in this invention are in the form ofthe alkali metal salts or ammonium salts of the acid. The polymerizablecomposition of the present invention may additionally comprise a solventselected from the group consisting of water, alcohols, esters, ethers,ketones, amides, sulfoxides, hydrocarbons and halogenated hydrocarbons.

The invention also relates to a free radical polymerization process andpolymers obtained thereby, which process overcomes many of the problemsand disadvantages of the afore mentioned prior art processes.

Therefore another subject of the present invention is a process forpreparing an oligomer, a cooligomer, a polymer or a copolymer (block orrandom) by free radical polymerization of at least one ethylenicallyunsaturated monomer/oligomer, which comprises (co)polymerizing themonomer or monomers/oligomers in the presence of an initiator compoundof formula (Ia) or (Ib) under reaction conditions capable of effectingscission of the O—R₃ (O—C) bond to form two free radicals, the radical.R₃ being capable of initiating polymerizabon.

Preferably the process is carried out in such a way that the scission ofthe O—C bond is effected by, heating ultrasonic treatment or exposure toelectromagnetic radiation, ranging from γ to microwaves.

More preferred the scission of the O—C bond is effected by heating andtakes place at a temperature of between 50° C. and 180° C.

Preferred initiators and ethylenically unsaturated monomers have alreadybeen mentioned above.

The process may be carried out in the presence of an organic solvent orin the presence of water or in mixtures of organic solvents and water.Additional cosolvents or surfactants, such as glycols or ammonium saltsof fatty acids, may be present. Other suitable cosolvents are describedhereinafter.

Preferred processes use as little solvents as possible. In the reactionmixture it is preferred to use more than 30% by weight of monomer andinitiator, particularly preferably more than 50% and most preferrablymore than 80%.

If organic solvents are used, suitable solvents or mixtures of solventsare typically pure alkanes (hexane, heptane, octane, isooctane),hydrocarbons (benzene, toluene, xylene), halogenated hydrocarbons(chlorobenzene), alkanols (methanol, ethanol, ethylene glycol, ethyleneglycol monomethyl ether), esters (ethyl acetate, propyl, butyl or hexylacetate) and ethers (diethyl ether, dibutyl ether, ethylene glycoldimethyl ether), or mixtures thereof.

The aqueous polymerization reactions can be supplemented with awater-miscible or hydrophilic cosolvent to help ensure that the reactionmixture remains a homogeneous single phase throughout the monomerconversion. Any water-soluble or water-miscible cosolvent may be used,as long as the aqueous solvent medium is effective in providing asolvent system which prevents precipitation or phase separation of thereactants or polymer products until after all polymerization reactionshave been completed. Exemplary cosolvents useful in the presentinvention may be selected from the group consisting of aliphaticalcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkylpyrrolidinones, N-alkyl pyrrolidones, polyethylene glycols,polypropylene glycols, amides, carboxylic acids and salts thereof,esters, organosulfides, sulfoxides, sulfones, alcohol derivatives,hydroxyether derivatives such as butyl carbitol or cellosolve, aminoalcohols, ketones, and the like, as well as derivatives thereof andmixtures thereof. Specific examples include methanol, ethanol, propanol,dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol,dipropylene glycol, tetrahydrofuran, and other water-soluble orwater-miscible materials, and mixtures thereof. When mixtures of waterand water-soluble or water-miscible organic liquids are selected as theaqueous reaction media, the water to cosolvent weight ratio is typicallyin the range of about 100:0 to about 10:90.

When monomer mixtures or monomerloligomer mixtures are used, thecalculation of mol-% is based on an average molecular weight of themixture.

Hydrophilic monomers, polymers and copolymers of the present inventioncan be separated from one another or from the polymerization reactionmixture by, for example, changing the pH of the reaction media and byother well known conventional separation techniques.

The polymerization temperature may range from about 50° C. to about 180°C., preferably from about 80° C. to about 150° C. At temperatures aboveabout 180° C., the controlled conversion of the monomer into polymerdecreases, and uncertain and undesirable by-products like thermallyinitiated polymer are formed or destruction of the polymerizationregulator may occur. Frequently, these by-products discolor the polymermixture and a purification step may be required to remove them, or theymay be intractable.

Therefore the surprisingly high reactivity of the present initiatorswhich are already active at relatively low temperatures leads to shortreaction times. The resulting polymers are usually colourless and theycan be used in most cases without any further purification step. This isan Important advantage when industrial scale-up is considered.

After the polymerizing step is complete, the formed (co)polymer obtainedis isolated. The isolating step of the present process is conducted byknown procedures, e.g. by distilling off the unreacted monomer or byprecipitation in a suitable nonsolvent, filtering the precipitatedpolymer followed by washing and drying the polymer.

Another preferred process is for preparing a block copolymer involvingat least two stages, which comprises forming a polymer with alkoxyamineend groups of the general structure of formula (IVa) or (IVb)

wherein R₁, R₂ and A are as defined above including the preferences, thepolymer containing the initiator group —R₃ and having the oxyamine groupessentially attached as terminal group, and adding a further monomerfollowed by heating to form a block copolymer by radical initiatedpolymerization.

Suitable monomers and comonomers are already mentioned.

The polymer of formula (IVa) or (IVb) may be isolated prior to the nextreaction step or it may be used without isolation, and the secondmonomer is added to the reaction mixture of the first step.

Furthermore, block copolymers of this invention, wherein the blocksalternate between polar monomers and non-polar monomers, are useful inmany applications as amphiphilic surfactants or dispersants forpreparing highly uniform polymer blends.

The (co)polymers of the present invention may have a number averagemolecular weight from 1 000 to 400 000 gmol, preferably from 2 000 to250 000 gmol and, more preferably, from 2 000 to 200 000 gmol. Whenproduced in bulk, the number average molecular weight may be up to 500000 (with the same minimum weights as mentioned above). The numberaverage molecular weight may be determined by size exclusionchromatography (SEC), gel permeation chromatography (GPC), matrixassisted laser desorptlonfionization mass spectrometry (MALDI-MS) or, Ifthe initiator carries a group which can be easily distinguished from themonomer(s), by NMR spectroscopy or other conventional methods.

Thus, the present invention also encompasses in the synthesis novelblock, multi-block, star, gradient, random, hyperbranched and dendriticcopolymers, as well as graft or copolymers.

The polymers prepared by the present invention are useful for example infollowing applications:

adhesives, detergents, dispersants, emulsifiers, surfactants, defoamers,adhesion promoters, corrosion inhibitors, viscosity improvers,lubricants, rheology modifiers, impact modifiers, thickeners,crosslinkers, paper treatment, water treatment, electronic materials,paints, coatings, photography, ink materials, imaging materials,superabsorbants, cosmetics, hair products, preservatives, biocidematerials or modifiers for asphalt, leather, textiles, ceramics andwood.

Because the present polymerizaton is a “living” polymerization, it canbe started and stopped practically at will. Furthermore, the polymerproduct retains the functional alkoxyamine group allowing a continuationof the polymerization in a living matter. Thus, in one embodiment ofthis invention, once the first monomer is consumed in the initialpolymerizing step a second monomer can then be added to form a secondblock on the growing polymer chain in a second polymerization step.Therefore it is possible to carry out additional polymerizations withthe same or different monomer(s) to prepare multi-block copolymers.Furthermore, since this is a radical polymerization, blocks can beprepared in essentially any order. One is not necessarily restricted topreparing block copolymers where the sequential polymerizing steps mustflow from the least stabilized polymer intermediate to the moststabilized polymer intermediate, such as is the case in ionicpolymerization. Thus it is possible to prepare a multi-block copolymerin which a polyacrylonitrile or a poly (meth)-acrylate block is preparedfirst, then a styrene or butadiene block is attached thereto, and so on.

Furthermore, there is no linking group required for joining thedifferent blocks of the present block copolymer. One can simply addsuccessive monomers to form successive blocks.

A plurality of specifically designed polymers and copolymers areaccessible by the present invention, such as star and graft (co)polymersas described, inter alia, by C. J. Hawker in Angew. Chemie, 1995, 107,pages 1623-1627, dendrimers as described by K. Matyaszewski et al. inMacromolecules 1996, Vol 29, No. 12, pages 4167-4171, graft (co)polymersas described by C. J. Hawker et al. in Macromol. Chem. Phys. 198,155-166(1997), random copolymers as described by C. J. Hawker InMacromolecules 1996, 29, 2686-2688, or diblock and triblock copolymersas described by N. A. Listigovers in Macromolecules 1996, 29, 8992-8993.

A further subject of the present invention is a polymer or oligomer,containing at least one initiator group —R₃ and at least one oxyaminegroup of formula

or

wherein A, R₁ and R₂ are as defined above, obtainable by the processdefined above.

Still another object of the present invention is the use of a compoundof formula (Ia) or (Ib) as defined above, including the preferences, forpolymerizing ethylenically unsaturated monomers.

The compounds of formula (Ia) or (Ib) may also be useful for terminatingthe anionic polymerization of butadiene. A process for the preparationof such nitroxyl terminated diene rubbers and suitable vinyl aromaticmonomers are for example disclosed in WO 97/36894.

The nitroxyl terminated diene rubbers produced using the compounds offormula (Ia) or (Ib), preferably those of formula (Ib), will have atleast one nitroxyl group attached to a chain-end. Typically, the dienemonomer is polymerized under anionic polymerization conditions andterminated in the presence of the nitroxyl containing compound.Preferably the diene monomer is a 1,3-conjugated diene such asbutadiene, isoprene or chloroprene. At temperatures above approximately60° C., the nitroxyl containing macrocompound activates to form a stablefree radical. If activation occurs in the presence of vinyl aromaticmonomers, such as styrene, a vinyl aromatic polymer segment is formed.These rubber modified styrene polymers lead for example to high impactstyrene (HIPS), impact polystyrene(IPS) or acryl-butadiene-styrenerubbers (ABS).

The compounds of the present invention may be prepared in different waysaccording to known methods. These methods are for example described inMacromol. Rapid Commun. 17, 149,1996, Macromol Symp. 111, 47, (1996),Polym. Degr. Stab. 55, 323 (1997), Synlett 1996, 330, U.S. Pat. No.5,498,679 or U.S. Pat. No. 4,921,962.

The method of reacting the nitroxyl with the corresponding ethyleneglycidylether in the presence of tert. butyl hydroperoxide as describedin U.S. Pat. No. 4,921,962 is a preferred method. As described inTetrahedron Lett 37, 4919, 1996 the reaction may also be carried outphotochemically in the presence of di-tert. butyl peroxide.

The starting compounds, which are phenylglycidylethers are known andeither commercially available or may be prepared according to EP 226543.

The following examples illustrate the invention.

A) Preparation of Compounds Example A12,2,6,6-Tetramethyl-1-(1-(4-oxiranylmethoxy-phenyl)-ethoxy)-4-propoxy-piperidine(101)

A: A 70% aqueous solution of terL-butylhydroperoxyde (26,4 g) isextractively dehydrated in two portions with each of 25 g2-(4-ethyl-phenoxymethyl)-oxirane. The organic extracts are combined, amolecular sieve is added and the mixture is stored under argonatmosphere.

B: A mixture of 2-(ethyl-phenoxymethyl)-oxirane (57 g),4-propoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (10,7 g) andmolybdenum(VI)oxide (0,72 g) are purged with Argon for one hour. Themixture is then heated up to 70° C. and the solution prepared under A)is added under stirring within 30 minutes. Pressure is reduced to 200mbar and the mixture is heated for 18 hours at 100° C. After thereaction is completed the mixture is cooled to room temperature and thepressure is allowed to raise to normal pressure. Ethylacetate and wateris added. The water phase is separated and extracted once withethylacetate. The organic phases are combined, washed with a 10%solution of sodium ascorbate and in a second step with water, dried oversodium sulfate and concentrated. Excessive amounts of2-(4ethyl-phenoxymethyl)-oxirane are removed at 80° C./0,01 mbar. Theraw product is subsequently chromatographically purified on silica withpetrolether/ethylacetate =7/1 as eluent. A clear colorless oil isobtained, corresponding to the compound of formula (101)

Elemental Analysis: calculated C₂₃H₃₇NO₄: 70,55% C; 9,52% H; 3,57% N.found: 70,66% C; 9,60% H; 3,43% N.

Example A22,2,6,6-Tetramethyl-1-[1-(2-oxiranylmethoxy-phenyl)-ethoxyl-]4-propoxy-piperidine(102)

A: To 18 g of a 70% aqueous solution of tert.-butylhydroperoxide isadded 9,9 g of 2-(2-ethyl-phenoxymethyl)-oxirane and 4 g of4-propoxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Water is separeted andthe organic phase dried over molecular sieve.

B: To a mixture of 4-propoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (6 g)and 2-(2-ethyl-phenoxymethyl)-oxirane (40 g) molybdenum(VI)oxyde (0,13g) is added. The pressure is then reduced to about 500 mbar and themixture heated to 80° C. The solution prepared under A) is then addedunder stirring within ¾ h. Stirring is continued for another 16 h at 80°C./500 mbar. The reaction mixture is then cooled to room temperature andthe pressure is allowed to raise to normal pressure. Ethylacetate and anaqueous solution of ascorbinic acid (20%) are added and the mixturestirred for another hour. The water phase is separated off, the organicphase washed three times with water and dried over sodium sulfate. Afterfiltration and evaporating off the solvent excessive2-(2-ethyl-phenoxymethyl)-oxirane is distilled off (0,08 mbar/70° C.).The residue is purified by column chromatography on silica gel withpetrolether/ethylacetate=9:1 as the eluent. The product corresponding toformula

is obtained as a resin.

¹H-NMR (300 MHz): 0.7-2.0 (m, 24H); 2.7-2.85 (m, 1H); 2.85-3.0 (m, 1H);3.3-3.6 (m 4H); 3.9-4.1 (m, 1H); 4.15-4.25 (m, 1H); 5.2 (q, 1H);6.75-7.5 (aromatic H, 4H).

Example A3 N,N-Di-tert.-butyl-O-[1-(4-Oxiranylmethoxy-phenyl)-ethyl]-hydroxylamine

A: A 70% aqueous solution of tert.-butylhydroperoxide (5.35 g) isextracted with two portions with each of 5 g2-(4ethyl-phenoxymethyl)-oxirane. The organic extracts are combined anddried over molecular sieve.

B: To a mixture of di-tert.-butylnitroxyl (2,2 g) and2-(4ethyl-phenoxymethyl)-oxirane (9,7 g) molybdenum(VI)oxyde (0,14 g) isadded. The pressure is then reduced to about 500 mbar and the mixtureheated to 80° C. The solution prepared under A) is then added understirring within 1,5 h. Stirring is continued for another 16 h at 80°C./500 mbar. The reaction mixture is cooled to room temperature and thepressure is allowed to raise to normal pressure. After dilution witethylacetate the mixture is filtered through a short column of alumina.The ethyl acetate solvent is evaporated and the residue distilled in aKugelrohr oven (0,08 mbar/100° C.) to remove excessive amounts of2-(4-ethyl-phenoxymethyl)-oxirane. After column chromatography on silicagel with petrolether/ethylacetate ═9:1 as the eluent, the productcorresponding to formula (103)

is obtained as a resin.

¹H-NMR (300 MHz): 1.0 (s, 9H); 1.3 (s, 9H); 1.46 (d, 3H); 2.73-2.77 (m,1H);288-292 (m, 1H); 3.32-3.38 (m, 1H); 3.92-4.01 (m, 1H); 4.16-4.22 (m,1H); 4.77 (q, 1H); 6.84+7.23 (AA′BB′-system, 2×2H).

Example A4 Preparation of1{-(4-[1-(2,2,6,6-Tetramethyl-piperidin-1-yloxy)-ethyl]-phenyl}-ethanone

A: A 70% aqueous solution of tert.-butylhydroperoxyde (26.4 g) isextractively dehydrated in two portions with each of 30 g4-ethylacetophenone. The organic extracts are combined, a molecularsieve is added and the mixture is stored under argon atmosphere.

B:,A mixture of 4-ethylacetophenone (23 g),2,2,6,6-tetramethylpiperidine-1-oxyl (10,7 g) and molybdenum(VI)oxide(0,67 g) are purged with Argon for one hour. The mixture is then heatedup to 70° C. and the solution prepared under A) is added drop wise understirring within 5 minutes. Pressure is reduced to 300 mbar and themixture is heated for 18 hours at 70° C. After the+reaction is completedthe mixture is cooled to room temperature and the pressure is allowed toraise to normal pressure. Ethylacetate and water is added. The waterphase is separated and extracted three times with ethylacetate. Theorganic phases are combined, washed with water, dried over Magnesiumsulfate and concentrated. Excessive amounts of2-(4-ethyl-phenoxymethyl)-oxirane are removed at 40° C./0,2 mbar. Theraw product is subsequently chromatographically purified on silica withpetrolether/ethylacetate=95/5 as eluent. A white+powder is obtainedafter recrystalization from pentane, corresponding to the compound offormula (104), having a melting point of 61.5-63° C.

Elemental Analysis: calculated C₁₉H₂₉NO₂ 75.21% C, 9.63% H, 4.61% N;found 75.09% C, 9.46% H, 4.37% N.

The examples given in table 1 are prepared in analogy to example A1 andA2.

TABLE 1 Example No. Formula Data A5

¹H-NMR: (in ppm, 300 MHz) 0.5-1.7(m, 18H,); 1.45(d, 3H); 2.7-2.76 (m,1H); 2.83-2.93(m, 1H); 3.28-3.4(m, 1H); 3.89-3.96(m, 1H); 4.14-4.2(m,1H); 4.73(q, 1H); 6.85+7.23(aromatic H, 2x2H) A6

0.5-2.0(m, 24H); 2.7-2.8(m, 1H); 2.85- 2.95(m, 1H); 3.2-3.6(m, 4H);3.9-4.1(m, 1H); 4.1-4.25(m, 1H); 4.74(q, 1H); 6.7- 7.3(aromatic H, 4H)A7

0.3-1.0(4t, 12H); 1.49(d, 3H); 1.5-2.25 (m, 8H); 2.7-2.8(m, 1H);2.85-2.95(m, 1H); 3.3-3.4(m, 1H); 3.9-4.05(m, 1H); 4.1-4.25(m, 1H);4.73(q, 1H); 6.75-7.35 (aromatic H, 8H) A8

Elemental Analysis: calc. C₂₆H₄₃NO₄: 72.02% C, 9.99% H, 3.23% N. found:72.04% C, 9.87% H, 3.31% N. A9

Elemental Analysis: calc. C₂₇H₃₅NO₅: 71.49% C, 7.78% H, 3.08% N. found:71.24% C, 7.92% H, 3.03% N.  A10

¹H-NMR: (in ppm, 300 MHz) 0.5-1.8(m, 16H); 1.38(d, 3H); 2.67-2.70 (m,1H); 2.81-2.85(m, 1H); 3.2-3.3(m, 1H); 3.9-4.2(m, 4H); 4.65(q, 1H);6.79+ 7.15(aromatic H, 2x2H). m.p. 60.8-61.4° C.  A11

m.p. 63-66° C.

The examples given in table 2 are prepared analogously to example A4.

TABLE 2 Example No. Formula Data A12

m.p. 44-46° C. A13

m.p. 90-92° C. A14

m.p. 72° C. A15

m.p. 81-82° C. A16

m.p. 43-47° C. A17

0.5-2.0(m, 19H); 2.6(s, 3H); 3.6-3.75 (m, 1H); 4.5(s, 2H); 4.84(q, 1H);7.2- 7.5(aromatic H, 7H); 7.9-8.0(aromatic H, 2H); resin

Table 3 gives further suitable compounds, which may be prepared inanalogy.

TABLE 3 Example No. Formula A18

A19

A20

 A21*

A22

A23

A24

A25

B Polymerizations Example B1 Styrene Polymerization

In a Schienk tube2,2,6,6-tetramethyl-1-[1-(4-oxiranylmethoxy-phenyl)-ethoxy]-4-propoxy-piperidine(compound 101) are dissolved in 50 ml of distilled styrene. The solutionis degassed according to the freeze and thaw technique and flushed withargon. After heating for 6 h in an oil bath to the temperature given intable 4 the excess monomer is removed in vacuum and the resulting whitepolymer is dried in a drying oven under vacuum. Weight average (Mw) andnumber average (Mn) molecular weights are determined using gelpermeation chromatography (GPC). The results are given in Table 4

TABLE 4 Temp. Nitroxide Conversion No. (° C.) (g, moles) (%) Mw Mn Mw/Mn1 120 0.170, 36 45500 32800 1.39 4.35 × 10⁻⁴ 2 120 0.392, 16 13480 86201.56 1.00 × 10⁻³ 3 130 0.170, 52 59400 44100 1.32 4.35 × 10⁻⁴

What is claimed is:
 1. A compound of formula (Ib)

wherein the R₂ are independently CH₃ or C₂H₅; A is a divalent grouprequired to form a cyclic 5-or 6- membered ring and R₃ is a radical offormula (II)

 wherein X is phenylene, naphthylene or biphenylene; one R₁₂ is H andthe other R₁₂ is CH₃; D is a group

 or a group C(O)—R₁₃; R₁₃ is CH₃ and m is a number from 1 to
 2. 2. Acompound of formula (III) according to claim 1

wherein R₃ has the meaning as defined in claim 1; Y is H, OR₁₀, NR₁₀R₁₁,—O—C(O)—R₁₀ or NR₁₁—C(O)—R₁₀; R₁₀ and R₁₁ independently are hydrogen,C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkinyl or C₂-C₁₈alkyl which issubstituted by at least one hydroxy group or, if Y is NR₁₀R₁₁, takentogether, form a C₂-C₁₂alkylene bridge or a C₂-C₁₂-alkylene bridgeinterrupted by at least one O atom.
 3. A compound according to claim 2,wherein R₃ is

 or

Y is H, OR₁₀ or NR₁₀R₁₁, —O—C(O)—R₁₀ or NR₁₁—C(O)—R₁₀; R₁₀ and R₁₁ areindependently hydrogen or C₁-C₆alkyl.
 4. A polymerizable composition,comprising a) at least one ethylenically unsaturated monomer oroligomer, and b) an initiator compound of formula (Ib) according toclaim
 1. 5. A composition according to claim 4, wherein theethylenically unsaturated monomer or oligomer is selected from the groupconsisting of styrene, substituted styrene, conjugated dienes, acrolein,vinyl acetate, (alkyl)acrylic acidanhydrides, (alkyl)acrylic acid salts,(alkyl)acrylic esters or (alkyl)acrylamides.
 6. A composition accordingto claim 5 wherein the ethylenically unsaturated monomer is styrene,α-methyl styrene, p-methyl styrene or butadiene.
 7. A compositionaccording to claim 6, wherein the ethylenically unsaturated monomer isstyrene.
 8. A composition according to claim 4, wherein the initiatorcompound of formula (Ia) or (Ib) is preferably present in an amount of0.01 mol-% to 10 mol-%, based on the monomer, oligomer ormonomer/oligomer mixture used.
 9. A process for preparing an oligomer, acooligomer, a polymer or a copolymer (block or random) by free radicalpolymerization of at least one ethylenically unsaturatedmonomer/oligomer, which comprises (co)polymerizing the monomer ormonomers/oligomers in the presence of an initiator compound of formula(Ib) according to claim 1 under reaction conditions capable of effectingscission of the O—R₃ (O—C) bond to form two free radicals, the radical.R₃ being capable of initiating polymerization.
 10. A process accordingto claim 9, wherein the scission of the O—C bond is effected by heating,ultrasonic treatment or exposure to electromagnetic radiation, rangingfrom γ to microwaves.
 11. A process according to claim 9, wherein thescission of the O—C bond is effected by heating and takes place at atemperature of between 50° C. and 180° C.
 12. A process according toclaim 9 for preparing a block copolymer involving at least two stages,which comprises forming a polymer with alkoxyamine end groups of thestructure of formula (IVb)

wherein the R₂ are independently CH₃ or C₂H₅ and A is a divalent grouprequired to form a cyclic 5-or 6- membered ring and R₃ is a radical offormula (II)

 wherein X is phenylene, naphthylene or biphenylene; one R₁₂ is H andthe other R₁₂ is CH₃; D is a group

 or a group C(O)—R₁₃; R₁₃ is CH₃ and m is a number from 1 to 2, thepolymer containing the initiator group —R₃ and having the oxyamine groupessentially attached as terminal group, and adding a further monomerfollowed by heating to form a block copolymer by radical initiatedpolymerization.
 13. A polymer or oligomer, containing at least oneinitiator group —R₃ and at least one oxyamine group of formula

wherein the R₂ are independently CH₃ or C₂H₅; A is a divalent grouprequired to form a cyclic 5-or 6- membered ring and R₃ is a radical offormula (II)

 wherein X is phenylene, naphthylene or biphenylene; one R₁₂ is H andthe other R₁₂ is CH₃; D isa group

 or a group C(O)—R₁₃; R₁₃ is CH₃ and m is a number from 1 to 2, obtainedby the process according to claim 9.